Siemens 3RU2146-4JB0 Three Phase Overload Relay

Siemens 3RU2146-4JB0 is a SIRIUS three-phase thermal overload relay (Size S3) designed to mount on compatible Sirius contactors for motor protection. It covers a current range of 45 to 63 A and features screw terminals for both the main circuit and the auxiliary circuit, with a reset option that can be set to manual or automatic. The unit includes phase-loss protection and provides one normally open and one normally closed auxiliary contact for simple interlocking with control circuits. Rated for up to 690 V AC, the 3RU2146-4JB0 is part of the 3RU2 family and is intended for use with Sirius contactors such as the 3RT2045, 3RT2046, and 3RT2047. The device is classified as Size S3 with Class 10 thermal protection, offering robust motor protection in industrial control panels and machine tools. Its plug-in design supports straightforward replacement within modular Sirius assemblies, making it a common choice for safeguarding motors in applications like conveyors, pumps, and fans where reliable overload detection and resettable protection are required.